This disclosure relates generally to the control and management of automated production systems, and more particularly to applying self-synchronization for model-based planning and scheduling of modular production systems to improve productivity.
Modular production systems utilizing multiple components or resources to perform a task may be executing sub-optimally if those components are not synchronized with respect to each other. An example is a printing system with a duplex loop, where the total loop time (from printing one page to printing the other page) should be an integral multiple of the time to print one image, which ensures that the full productivity of the printer is used. Traditionally, known configurations have been optimized “by hand” such that self-synchronization is assured, but new systems composed of modular components and multiple, cooperating resources require an automated method to achieve this self-synchronization.
In existing systems, self-synchronization is often achieved through analysis of a given, fixed system configuration and the tuning of system parameters (e.g., the dimensions or timing of its components). For example, for print production systems, manual or spreadsheet-based analysis would typically be used to determine the required dimensions and timing of components in order to achieve optimal productivity of the system. For print production systems, this analysis is typically restricted to a linear configuration of printers and their duplex loops. This can be seen in U.S. Pat. No. 6,095,043 to Hartmann et al., in which two printing units in a linear sequential configuration and a transfer unit are synchronized for paper movement, and in U.S. Pat. No. 6,592,121 to Frank et al., in which a transport system provides synchronization of a transport device conveying sheet material to insure collision-free transport. However, this art is directed to standard print system configurations and does not address the problems associated with systems having multiple operational modules.
In the printing domain, there are few products with tandem configurations (two or more tightly coupled printer modules) and even fewer with redundant paths between the main productivity-determining resources (printers), i.e., configurations are typically simple and easy to analyze. The state of the art in other domains, e.g., assembly lines, also often rely on manual fine-tuning for particular configurations (e.g., automotive production plants), or it is assumed that there are buffers between the production modules where parts can be stored, i.e., modules are only loosely coupled. While an alternative is not to optimize a configuration and live with sub-optimal productivity, this is often not an acceptable approach, since it may leave expensive equipment partly idle.